The liberal Web site Daily Kos, hoping to "make mischief for the Republican Party -- and bolster the Democrats' chances for taking the White House" -- is urging Democrats in Michiagn to cross over and vote for Mitt Romney in Tuesday's state primary.

It's a classic dirty trick, but perfectly legal. And while Machiavellian political ploys of this sort rarely work, the author's logic is thus:

A Romney victory in Michigan will keep him in the presidential race. And the more candidates slugging it out among the Republicans, the better for the Democrats.

John McCain is riding high after his resounding win in the New Hampshire primary Tuesday, and Mike Huckabee's star is still shining following his Iowa win. With South Carolina posing an opportunity for either candidate to continue the momentum, Romney needs to win in his native Michigan to stay competitive.

The former Massachusetts governor is already spending almost all his time there, and he repeatedly says he's going to win.

Says the Kos, "And we want Romney in, because the more Republican candidates we have fighting it out, trashing each other with negative ads and spending tons of money, the better it is for us. We want Mitt to stay in the race, and to do that, we need him to win in Michigan."

Click here to read 'Let's Have Some Fun in Michigan' on the Daily Kos.

The "fun" is no skin off Democrats' backs, argues Daily Kos. Michigan already lost its delegates to the Democratic National Convention for scheduling an early primary, so the state's primary is basically meaningless for the Democratic candidates, who are focusing now on South Carolina and Nevada.

But on the GOP side, it's still competitive.

In almost every election cycle, similar crossover voting is talked about. However, it seldom has an impact.

FOX News' Carl Cameron contributed to this report.